<!DOCTYPE html>
<html lang="zh-CN">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>媒体查询</title>
    <style>
      @media screen and (min-width: 300px) and (max-width: 500px) {
        html {
          font-size: 30px;
        }
      }
    </style>
  </head>
  <body>
    <p>你好呀~~</p>
  </body>
</html>
